pinger-async-await.js

import _ from 'lodash';
import fetch from 'node-fetch';
import delay from 'delay';

export async function pingServers(servers) {
  let failedServers = {};
  for (const url of servers) {
    let failures = 0;
    for (const i of _.range(3)) {
      const response = await fetch(url);
      if (!response.ok) failures++;
      await delay(10000);
    }
    if (failures > 0) failedServers[url] = failures;
  }
  return failedServers;
}

I definitely love the async/await features coming to Node.
But, still, on "back-end" environments, GO might subjectively be better and might objectively outperform Node in multi-processor environments. The difference in performance between Node and GO might be negligible in single-processor environments.

For comparison purposes, here is my simple implementation of your pinger-async-await.js in GO: https://gist.github.com/pmbenjamin/c9dad251f6c8cd83bb6e5e9dbc8e883c